Under the Clean Air Act (CAA or ``Act''), the Environmental Protection Agency (EPA) is taking final action to approve a request from the State of California to reclassify the San Diego County ozone nonattainment area from ``Serious'' to ``Severe'' for the 2008 ozone National Ambient Air Quality Standards (NAAQS) and from ``Moderate'' to ``Severe'' for the 2015 ozone NAAQS. The EPA is also finalizing our action to reclassify in the same manner as state land, reservation areas of Indian country and any other area of Indian country within it where the EPA or a tribe has demonstrated that the tribe has jurisdiction located within the boundaries of the San Diego County ozone nonattainment area. The new applicable attainment dates for the San Diego County ozone nonattainment area are as expeditious as practicable but no later than July 20, 2027, for the 2008 ozone NAAQS, and August 3, 2033, for the 2015 ozone NAAQS. With respect to Severe state implementation plan (SIP) element submittal dates that have passed, the EPA is approving a deadline of no later than 12 months from the effective date of this rule for submittal of revisions to the San Diego County portion of the California SIP to meet additional requirements for Severe ozone nonattainment areas to the extent that such revisions have not already been submitted.